Mapping vacancy and bonding electron distributions around aluminium nanovoids

TL;DR

This paper introduces a novel method to measure and map bonding electron distributions around nanovoids in aluminium, revealing detailed 3D vacancy concentrations and the healing of radiation-damaged voids, with results aligning with theoretical predictions.

Contribution

A new experimental technique for 3D mapping of bonding electron densities around nanostructures and defects in materials is demonstrated, enabling insights into nanostructure effects on material properties.

Findings

Measured vacancy volume with 3% uncertainty.

Mapped vacancy concentrations with nanometre resolution.

Observed healing of radiation-damaged voids.

Abstract

All materials have defects and many contain nanostructures, both of which disrupt chemical bonding - the basis of materials properties. No experimental measurements of bonding electron distributions associated with defects and nanostructures have ever been possible. We present a method enabling such measurements and interrogate nanovoids surrounded by vacancies - the most fundamental of nanostructures and defects - in aluminium. We measure the volume of a vacancy with 3% uncertainty and map vacancy concentrations surrounding nanovoids with nanometre resolution in three dimensions where previously only two-dimensional mapping was possible. We discover that radiation-damaged voids can "heal". Our bonding measurements are depth-resolved, vacancy-sensitive, and agree with density functional theory. This work opens bonding electron density measurements to inhomogeneous nanostructured multi-phased materials so that the electronic origins of phenomena such as strengthening, weakening, interface functionality, solute diffusion and phase transformations within them may be revealed.